1. Field of the Invention
The invention discloses novel polyester emulsifiers. Compounds of the invention are made by reacting (a) a dimethicone copolyol, (b) a diacid and (c) a fatty alcohol alkoxylate containing 4 to 20 carbon atoms. The compounds of the invention by virtue of (a) the silicone group, (b) the fatty alcohol terminal group and (c) the polyoxyalkylene present in the compound are extremely efficient emulsifiers for a variety of oils at heretofore unknown levels.
The esterification by which the compounds are prepared is the reaction of a dimethicone copolyol, a hydroxy containing silicone polymer which may contain varying amounts of polyoxyalkylene in the molecule, a dicarboxylic acid and a fatty alcohol alkoxylate. Since the fatty alkoxylate contains only one hydroxyl group, it will become a terminal group in the polyester.
2. Arts and Practices
Silicone compounds have been known to be active at the surface of plastic, cellulosic and synthetic fibers as well as paper. They are good nondurable lubricants and are very stable to oxidation, however, their high cost and lack of efficiency at low concentrations as well as low durability have made their acceptance in commercial products quite low. In all instances, commercially available quaternaries are the active ingredient in traditional laundry care markets, with little or no silicone added.
The low efficiency and low durability of dimethylpolysiloxane is due to the fact that it is very water insoluble and deposits on the surface to obtain a minimum free energy in the solution. Simply, the silicone oil delivery to the surface by hydrophobic binding, not chemical bonding. At the surface, the dimethylpolysiloxane is a very effective fiber lubricant, however, there are two drawbacks, first; the dimethylpolysiloxane is not chemically bonded so the effect is very transient and disappears with one washing, and second; since there is no reaction of the dimethylpolysiloxane to the surface an equilibrium between fiber absorbed dimethylpolysiloxane and dimethylpolysiloxane in the dispersion results in very inefficient percentage of silicone deposited. A large amount of the expensive silicone goes down the drain with the waste water.
In many applications, there is a strong desire to obtain a solid wax which can be used in applications were a spread on application is of interest. These applications include personal care applications like antiperspirants and skin creams. Unfortunately most silicone derivatives are liquid to very low temperatures. Attempts to overcome this deficiency have been made by reacting stearyl alcohol with a chloro silane. The difficulty with the use of this type of material is that a large excess (50% by weight) of the alcohol needs to be added to get a product which is free of the irritating chlorosilane raw material. When such an excess is used the product behaves functionally more like the stearyl alcohol than like a silicone compound. Additionally, the compound is not polymeric, hence the superior lubrication and hydrophobicity enhancements which can be achieved by dimethylpolysiloxane is not obtainable with these compounds.
U.S. Pat. No. 3,511,699 to Sterman issued May 12, 1970 teaches that epoxy compounds placed in the silicone backbone by hydrosilation can be cured onto certain fibers to give improved substantivity. The substantivity is based upon the reaction of hydroxyl groups on the cellulosic and the epoxy group in the silicone polymer. The resulting bond is a ether linkage and a new hydroxyl group. While a definite improvement over other compounds the efficiency and durability of the were not good enough to allow for cost effective incorporation of these materials in detergent formulations.
U.S. Pat. No. 5,051,489 issued to O'Lenick, Jr. teaches that silicone esters can be prepared by the reaction of silanols and fatty acids. These compounds lack fatty alkoxy group needed for emulsification.